Affiliation:
1. Center for Nanoscale Characterization & Devices (CNCD) Wuhan National Laboratory for Optoelectronics (WNLO) and School of Physics Huazhong University of Science and Technology (HUST) Wuhan 430074 P. R. China
2. Information Materials and Intelligent Sensing Laboratory of Anhui Province Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education Institutes of Physical Science and Information Technology Anhui University Hefei 230601 P. R. China
3. Hubei key laboratory of energy storage and power battery School of Mathematics Physics and Optoelectronic Engineering Hubei University of Automotive Technology Shiyan 442002 P. R. China
Abstract
AbstractHigh‐safety potassium‐ion batteries (HPIBs) are highly intriguing owing to their green energy, low cost, high voltage, noncombustible, and simple assembly. However, most high‐voltage HPIBs use water‐in‐salt electrolytes (WISE), which lead to several problems, such as a high viscosity, which significantly reduces the performance and increases the cost of HPIBs, thus impeding their development. Unfortunately, studies regarding HPIB electrolytes remain limited, further limiting the development of HPIBs. Herein, a co‐solvent engineering electrolyte (4.0 m KOTf in a mixture of propylene carbonate (PC) and H2O with a volume ratio of 5.0:1.0) featuring low‐cost (1/4 of WISE) and high‐performance (45.43 mS cm−1) characteristics is proposed, which not only achieves a wide electrochemical stability window by reducing the activity of H2O, but also adjusts the solvation structure of K+. Consequently, the HPIBs assembled via co‐solvent engineering electrolyte demonstrated a high energy density of 88.05 Wh kg−1, and sufficiently operated at rates of 0.50–10.0 A g−1 over a wide temperature range (−25–50 °C). This study provides a promising means for developing high‐voltage HPIBs.
Funder
National Natural Science Foundation of China
China Postdoctoral Science Foundation